Camera unit and sensing device

ABSTRACT

A camera unit includes: an image sensor; a circuit board in which a signal processor circuit to process an output signal of the image sensor is formed; a cable including at least a signal conductor element and a ground conductor element and connected at one end to the circuit board; a metal housing component to accommodate the image sensor and the circuit board therein; and a metal component disposed at the end of the cable and connected to the ground conductor element. The ground conductor element is connected to both a ground terminal of the circuit board and the metal housing component in a vicinity of the end of the cable where the cable is connected to the circuit board. The ground conductor element is connected to the metal housing component through the metal component in the vicinity of the end of the cable.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation patent application of, and claims thebenefit of and priority to U.S. patent application Ser. No. 14/167,004filed on Jan. 29, 2014 that is a continuation patent application of, andclaims the benefit of and priority to U.S. patent application Ser. No.12/846,993 filed on Jul. 30, 2010, which is based on and claims thebenefit of priority of Japanese Patent Application No. 2009-180274,filed on Aug. 3, 2009, with the Japanese Patent Office, the entirecontents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present disclosure relates to a camera unit which outputs an imagesignal, and relates to a sensing device including a camera unit whichoutputs an image signal.

2. Description of the Related Art

An in-vehicle camera which is used in an automotive vehicle isexternally attached to the vehicle, and it is required that thein-vehicle camera has a high waterproofing performance although thein-vehicle camera is small in size. A cable needed for the wiring thatconnects the in-vehicle camera and a display unit internally arranged inthe vehicle is almost about 10 m long.

Generally, an automotive vehicle includes several sources ofelectromagnetic waves, such as an engine and motors. Electromagneticwaves emitted from such sources may affect the in-vehicle camera throughthe cable, such that noise is superimposed on an image captured by thecamera. Conversely, under the influence of electromagnetic waves emittedfrom the in-vehicle camera, an in-vehicle radio unit may be affectedthrough the cable, such that sound generated by the radio unit becomesnoisy. To eliminate the problem, it is important to take measuresagainst electromagnetic interference (EMI) for the in-vehicle camera.

Moreover, it is required that the in-vehicle camera normally operatesunder severe environmental conditions. When dry conditions are intense,such as in winter, and a user's hand touches the in-vehicle camera,electrostatic discharge occurs frequently. To protect the in-vehiclecamera from electrostatic discharge, it is required that the in-vehiclecamera has a high resistance to electrostatic discharge.

Japanese Laid-Open Patent Publication No. 2005-347243 discloses anin-vehicle camera in which a circuit board carrying electronic parts,such as a sensor and an image processing circuit, is accommodated in ahousing of the in-vehicle camera. If adequate EMI measures are not takenand high voltage due to electrostatic discharge is applied, it mayresult in malfunction of the in-vehicle camera or destruction of anelectronic part. The in-vehicle camera is concerned with the safetyperformance in vehicle operation, and malfunction of the in-vehiclecamera or destruction of the electronic part may significantly affect ahuman life. Hence, it is required to take adequate EMI measures for thein-vehicle camera.

In the in-vehicle camera according to the related art, a housing made ofan insulator, such as a plastic material, is used as the housing of thein-vehicle camera in order to prevent electrostatic discharge fromaffecting the camera.

Moreover, in the in-vehicle camera according to the related art, when aradiation source of electromagnetic waves exists inside the vehicle, ametal shield plate directly connected to a ground line (GND) of thecircuit board is arranged within the housing. As a countermeasure for acase in which electrostatic discharge takes place between a clearance inthe insulator and the metal shield plate or the circuit board, theground line (GND) of the circuit board is connected to a ground line ofan external power supply through the cable. This is a known technique.

Japanese Patent No. 3802742 discloses a connector which is used as anin-vehicle component other than an in-vehicle camera. This connector isarranged so that a metal exterior of the connector is enclosed with ametal part connected to a shielding wire of a cable, which causes staticelectricity to flow through an external ground line to which the cableis connected.

However, the in-vehicle camera according to the related art in which thecircuit board is enclosed with the housing of the insulator is directedto preventing occurrence of electrostatic discharge or reducing theoccurrence probability of malfunction of the camera or destruction ofthe electronic part. If no metal shield plate is internally arranged andelectrostatic discharge occurs, the portion of the circuit board wherethe discharge takes place is not predicted. Hence, takingcountermeasures or corrective actions requires much time.

Even if a metal shield plate is internally arranged, inside the circuitboard, static electricity discharged to the metal shield plate issupplied to the external ground line through the circuit board becausethe ground line (GND) of the circuit board and the metal shield plateare connected directly at a specific portion. In this case, a highvoltage due to the electrostatic discharge is applied to the circuitboard instantaneously, and the electronic parts in the circuit board areloaded with this high voltage. Therefore, it is difficult to certainlyavoid destruction of the electronic parts due to electrostaticdischarge.

Although enclosing the circuit board with the housing of the insulatormakes occurrence of electrostatic discharge difficult, once electricdischarge occurs, the instantaneous application of a high voltage to thecircuit board is unavoidable regardless of the use of a metal shieldplate.

A conceivable method for eliminating the problem is to arrangeelectronic parts which are vulnerable to a high voltage in the areas ofthe circuit board where the influences of electrostatic discharge aresmall. However, modification of the circuit board design is not easy tocarry out, and it is expected that taking countermeasures or correctiveactions requires much time and high cost.

In the connector disclosed in Japanese Patent No. 3802742, the metalexterior and the external ground line are electrically connected. Thisconnector provides a high resistance to electrostatic discharge.However, if this connector is used in an in-vehicle camera, electricalconnection between the metal part and the source of electromagneticwaves or the ground line (GND) of the circuit board is not provided, andit is difficult to provide adequate EMI measures.

SUMMARY OF THE INVENTION

In one aspect, the present disclosure provides a camera unit which iscapable of providing high resistance to electrostatic discharge and goodshielding performance of electromagnetic waves with low cost.

In another aspect, the present disclosure provides a sensing devicewhich is capable of providing good reliability with low cost.

In an embodiment which solves or reduces one or more of theabove-described problems, the present disclosure provides a camera unitincluding: an image sensor; a circuit board in which a signal processorcircuit to process an output signal of the image sensor is formed; acable including at least a signal conductor element and a groundconductor element and connected at one end to the circuit board; and ashielding component formed to enclose the circuit board therewith,wherein the ground conductor element is connected to both a groundterminal of the circuit board and the shielding component in a vicinityof the end of the cable where the cable is connected to the circuitboard.

In an embodiment which solves or reduces one or more of theabove-described problems, the present disclosure provides a sensingdevice including: a camera unit to capture an image indicatingsurroundings of the camera unit; and a display unit to display imageinformation based on an output signal of the camera unit, the cameraunit including: an image sensor; a circuit board in which a signalprocessor circuit to process an output signal of the image sensor isformed; a cable including at least a signal conductor element and aground conductor element and connected at one end to the circuit board;and a shielding component formed to enclose the circuit board therewith,wherein the ground conductor element is connected to both a groundterminal of the circuit board and the shielding component in a vicinityof the end of the cable where the cable is connected to the circuitboard.

Other objects, features and advantages of the present invention willbecome more apparent from the following detailed description when readin conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating the composition of a vehicle in whichan in-vehicle camera is arranged.

FIG. 2 is a block diagram illustrating the composition of a backmonitoring device (sensing device) of an embodiment of the presentdisclosure.

FIG. 3A, FIG. 3B and FIG. 3C are diagrams illustrating the compositionof an in-vehicle camera (camera unit) of an embodiment of the presentdisclosure.

FIG. 4 is a diagram illustrating a modification of a shield plate.

FIG. 5 is a block diagram illustrating the composition of a signalprocessor circuit.

FIG. 6 is a diagram illustrating the composition of a cable.

FIG. 7 is a diagram illustrating the composition of an end portion of acable which is connected to the in-vehicle camera.

FIG. 8 is a diagram illustrating the composition of an end portion of acable which is connected to the in-vehicle camera.

FIG. 9 is a diagram for explaining a process of connecting the cable tothe in-vehicle camera.

FIG. 10 is a diagram for explaining a process of connecting the cable tothe in-vehicle camera.

FIG. 11 is a diagram for explaining a process of connecting the cable tothe in-vehicle camera.

FIG. 12 is a diagram for explaining a process of connecting the cable tothe in-vehicle camera.

FIG. 13 is a block diagram illustrating the composition of a filtercircuit in a circuit board.

FIG. 14 is a diagram for explaining a method of connecting a shieldplate to a ground line in an in-vehicle camera according to the relatedart.

FIG. 15 is a diagram for explaining a method of connecting a shieldplate to a ground line in the in-vehicle camera of this embodiment.

FIG. 16 is a diagram for explaining a method of connecting a shieldplate to a ground line in the in-vehicle camera of this embodiment.

FIG. 17 is a block diagram illustrating the composition of a voice/alarmgenerating unit.

FIG. 18 is a diagram illustrating the composition of a modification ofthe cable.

FIG. 19 is a diagram illustrating the composition of a modification ofthe cable.

FIG. 20 is a diagram illustrating the composition of a modification ofthe cable.

FIG. 21 is a diagram for explaining the condition of an end portion ofthe cable when the cable of FIG. 20 is used.

FIG. 22 is a diagram illustrating a modification of a shield plate.

FIG. 23A and FIG. 23B are diagrams illustrating a modification of an endportion of a cable.

FIG. 24A, FIG. 24B and FIG. 24C are diagrams illustrating thecomposition of a crimping component which is used for the end portion ofthe cable of FIG. 23A.

FIG. 25 is a diagram illustrating the composition of the modification ofthe end portion of the cable of FIG. 23A.

FIG. 26A and FIG. 26B are diagrams illustrating the composition of themodification of the end portion of the cable of FIG. 23A.

FIG. 27 is a diagram illustrating the composition of the modification ofthe end portion of the cable of FIG. 23A.

FIG. 28A and FIG. 28B are diagrams illustrating a modification of theend portion of the cable.

FIG. 29 is a diagram illustrating the modification of the end portion ofthe cable FIG. 28A.

FIG. 30A and FIG. 30B are diagrams illustrating a modification of theend portion of the cable.

FIG. 31 is a diagram illustrating the modification of the end portion ofthe cable of FIG. 30A.

FIG. 32 is a diagram illustrating the modification of the end portion ofthe cable of FIG. 30A.

FIG. 33 is a diagram illustrating a modification of the end portion ofthe cable.

FIG. 34 is a diagram illustrating a modification of the end portion ofthe cable.

FIG. 35 is a diagram illustrating the modification of the end portion ofthe cable of FIG. 34.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A description will be given of embodiments of the present disclosurewith reference to the accompanying drawings.

FIG. 1 illustrates the composition of a vehicle 1 in which an in-vehiclecamera 20 is arranged.

For the purpose of assisting a driver's vision, an in-vehicle camera isinstalled at a rear portion, a front portion or a side portion of avehicle, so that an image indicating the surroundings of the vehiclecaptured by the camera is displayed on a display unit, such as a liquidcrystal display monitor, in the vehicle. In order to provide a safesystem without a dead angle, it is required that the in-vehicle camerahas a large viewing angle. In view of a vehicle design, it is desiredthat the in-vehicle camera is not conspicuous. Hence, it is alsorequired that the in-vehicle camera is of small size.

A back-monitor type camera which is a popular in-vehicle camera isexternally attached to the vehicle, and it is required that the camerahas a high waterproofing performance. Usually, an in-vehicle camera isinstalled in the vicinity of the trunk at the rear of the vehicle and adisplay unit is installed on the side of a driver's seat, and it isnecessary that a cable needed for the wiring that connects the cameraand the display unit is almost about 10 m long.

It is also required that the in-vehicle camera has a tensile strengththat can withstand the wiring, provides a function of preventingmalfunction of the camera due to electromagnetic waves emitted fromseveral sources of electromagnetic waves, and provides a function ofpreventing the adverse influences of electromagnetic waves emitted fromthe in-vehicle camera on an in-vehicle radio unit, such as an FM radioor an AM radio. It is also required that the in-vehicle camera has ahigh resistance to electrostatic discharge which may frequently occur inthe winter season.

In the vehicle 1 illustrated in FIG. 1, the in-vehicle camera 20 isexternally attached to a rear portion of the vehicle 1. In thefollowing, it is assumed that a forward direction of the vehicle 1 isthe +X direction of the X-axis of an XYZ three-dimensional orthogonalcoordinate system, a lateral direction of the vehicle 1 is the +Y or −Ydirection of the Y-axis thereof, and a gravity direction is the -Zdirection of the Z-axis thereof.

As illustrated in FIG. 2, an information processing device 30 whichprocesses image information from the in-vehicle camera 20 is disposedinside the vehicle 1. The information processing device 30 and thein-vehicle camera 20 are connected together via a cable 40.

The information processing device 30 includes an input/output interface31, a display unit 32, a main controller 33, a memory unit 34, and avoice/alarm generating unit 35. Power from a power-supply unit 50 issupplied to the information processing device 30.

In this embodiment, a back monitoring device 10 is constituted by thein-vehicle camera 20, the information processing device 30, and thecable 40.

As illustrated in FIGS. 3A to 3C, the in-vehicle camera 20 includes alens system 21, a camera housing 22, a CMOS (complementary metal oxidesemiconductor) image sensor 24, a circuit board 25, and a shield plate26. In this embodiment, one end of the cable 40 in the −X direction isconnected to the in-vehicle camera 20.

The lens system 21 is designed to have a wide angle of view which is ina range of 120 to 190 degrees in order to enable an image, indicatingthe surroundings of the vehicle 1 at the rear thereof including theright and left sides thereof, to be captured by the camera. For example,the lens system 21 is made up of six lenses in order to capture aquality image.

The camera housing 22 is formed of a resin molding and has a squarepole-like configuration. A holding part for holding the lens system 21is formed at one end of the camera housing 22 in the −X direction, andan opening for inserting the cable 40 is formed in the camera housing 22in the middle of the end face thereof at the other end of the camerahousing 22 in the +X direction. Two threaded holes for fastening thecable 40 to the camera housing 22 by screws are formed in the camerahousing 22 at right and left portions of this opening in the +Y and −Ydirections.

The camera housing 22 may be divided into two parts: a front case 22A onthe side of the camera housing 22 in the −X direction and a rear case22B on the side thereof in the +X direction. The front case 22A and therear case 22B are fitted together into an integral part.

An O-ring is attached to a clearance between the camera housing 22 andthe lens system 21 in order to prevent water or foreign matter fromentering the inside of the camera housing 22 from the clearance. Arubber packing is attached to the fitted portion of the front case 22Aand the rear case 22B in order to prevent water or foreign matter fromentering the interior of the camera housing 22 from the fitted portion.

The CMOS image sensor 24, the circuit board 25, and the shield plate 26are accommodated in the camera housing 22.

The CMOS image sensor 24 converts the incident light entering the sensorthrough the lens system 21 into an electrical signal. The CMOS imagesensor 24 is attached to the circuit board 25 through a ceramic package.

The shield plate 26 is a sheet-like shielding component which is made ofstainless steel, phosphor bronze, etc. and has a thickness of about 0.2mm. The shield plate 26 is formed to enclose the circuit board 25therewith. An opening which is essentially the same as the opening ofthe camera housing 22 is formed in the portion of the shield plate 26which faces the opening of the camera housing 22. The shield plate 26has a function of shielding electromagnetic waves and a function ofreceiving electrostatic discharge. The shield plate 26 is attached to apredetermined position of the rear case 22B.

Alternatively, the shield plate 26 may be modified as illustrated inFIG. 4. In this modification, the shield plate 26 may be divided intotwo pieces: a shield plate 26A disposed in the front case 22A and ashield plate 26B disposed in the rear case 22B. It is necessary that,when the front case 22A and the rear case 22B are fitted together, thetwo shield plates 26A and 26B are in contact with each other throughleaf springs (made of a metallic material), so that the shield plates26A and 26B are electrically connected to each other.

In the circuit board 25, a signal processor circuit, an internal powersupply, etc. are formed. The circuit board 25 is attached to apredetermined position of the rear case 22B.

The signal processor circuit inputs an output signal of the CMOS imagesensor 24, processes the input signal by correcting the distortion andbrightness of an image indicated by the input signal, and outputs theprocessed signal as an analog video (NTSC) signal.

As illustrated in FIG. 5, the signal processor circuit includes aCDS/AGC circuit, an A/D converter, a DSP (digital signal processor), aD/A converter, and an encoder.

The CDS/AGC circuit includes a CDS (correlated double sampling) circuitand an AGC (automatic gain control) circuit. The CDS circuit provides afunction of measuring electrical values of output signals of the CMOSimage sensor 24, such as voltages or currents, to allow for removal ofan undesired offset or reset noise contained in the output signals ofthe CMOS image sensor 24. The AGC circuit provides an automatic gaincontrol for sensor output signals in that the black level of the imagesignal is held at a constant level.

The A/D converter converts the analog signal output from the CDS/AGCcircuit into a digital signal. The DSP performs a predeterminedcompensation processing for the digital signal output from the A/Dconverter. The D/A converter converts the digital signal output from theDSP into an analog signal. The encoder converts the analog signal outputfrom the D/A converter into an analog video signal. The signal processorcircuit outputs this analog video signal as an output signal.

The internal power supply in the circuit board 25 supplies power fromthe cable 40 to the respective electronic parts fabricated in the CMOSimage sensor 24 and the circuit board 25.

FIG. 6 illustrates the composition of a cable 40. As illustrated in FIG.6, the cable 40 includes an analog signal line A1, a power supply lineA2, a ground line A3, and a shield material F as conductor elements.

The analog signal line A1 is a conductor element for transmitting animage signal from the in-vehicle camera 20 to the information processingdevice 30. The power supply line A2 is a conductor element for supplyingpower from the power supply unit 50 to the in-vehicle camera 20 throughthe information processing device 30.

Each of the analog signal line A1, the power supply line A2, and theground line A3 is enclosed with an insulator B, respectively. Each lineis formed into an insulated wire.

Using a bundling material D, the three insulated wires with an inclusionmaterial C are bundled together to have a generally circular crosssection. The bundling material D is enclosed with the shield material F,and further the shield material F is enclosed with an insulatingmaterial E as a sheath.

An example of the inclusion material C may be cotton yarn or a softresin. An example of the bundling material D may be paper or a tape. Anexample of the shield material F may be a braided or woven shield offine wires, or an aluminum tape. When an aluminum tape is used as theshield material F, at least one conductor line as a drain line iscontacted to the surface of the aluminum tape as illustrated in FIG. 6.This enables the work of connection processing at the end portion of thecable to be easily performed. The shield material F may be used as aground conductor element for taking preventive measures againstelectromagnetic waves and electrostatic discharge.

An example of the insulating material E may be nylon resin, polyethyleneresin, or urethane resin.

As illustrated in FIG. 7, the three insulated wires and the drain lineare exposed at the end of the cable 40 in the −X direction.

A block 41 which is made of a resin molding and includes two throughholes is bonded to a portion of the cable 40 in the vicinity of the endof the cable 40 in the −X direction. In this embodiment, a resin havinggood adherability to the insulating material E is used as the resinmaterial of the block 41. This helps prevent separation of the cable 40from the block 41 when the cable 40 is under tension.

Alternatively, a crimping ring may be fitted to the outer periphery ofthe insulating material E and the crimping ring may be formed of a resinmolding using a resin that is the same as the resin of the block 41.This helps prevent the sliding of the cable 40.

As illustrated in FIG. 8, a portion of the insulator B of each of thethree insulated wires (which are exposed from the cable 40) in thevicinity of the end of the cable 40 in the −X direction is removed.These insulated wires are inserted in a connector. The ground line A3and the drain line are bonded together in the vicinity of the connectorby soldering.

Next, a process of connecting the cable 40 and the in-vehicle camera 20will be described. It is assumed that the camera housing 22 is initiallydivided into the front case 22A and the rear case 22B, and the circuitboard 25 is not yet attached to the rear case 22B.

(1) As illustrated in FIG. 9, the end of the cable 40 in the −Xdirection is inserted into the camera housing 22 through the opening atthe end of the camera housing 22 in the +X direction and the opening ofthe shield plate 26, and the block 41 is brought into contact with therear case 22B. At this time, an O-ring is attached to a recess betweenthe block 41 and the rear case 22B.

(2) As illustrated in FIG. 10, screws are respectively inserted in thethrough holes of the block 41 and fastened to the threaded holes formedin the rear case 22B. Thereby, the block 41 is fixed to the rear case22B by the screws. The use of the O-ring fitted between the block 41 andthe rear case 22B helps prevent water or foreign matter from enteringthe camera housing 22 from the clearance between the block 41 and therear case 22B.

(3) As illustrated in FIG. 11, the drain line and the shield plate 26are connected together by a lead wire. Thereby, the shield plate 26 iselectrically connected to both the ground line A3 and the drain line.

(4) As illustrated in FIG. 12, the connector of the cable 40 isconnected to a terminal base provided in the circuit board 25, and thecircuit board 25 is attached to the predetermined position of the rearcase 22B.

(5) The front case 22A is fitted to the rear case 22B.

On the other hand, a connector, such as an RCA jack, a DC plug or abullet terminal, is attached to the other end of the cable 40 in the +Xdirection. The cable 40 is connected to the input/output interface 31 ofthe information processing device 30 through this connector. The shieldmaterial F of the cable 40 is connected to a ground line of thepower-supply unit 50.

Generally, noise is mixed in a signal transmitted through a power supplyline and a ground line from an external device. As illustrated in FIG.13, a filter circuit is arranged in the circuit board 25 to remove noisefrom the signal received from the external device. The ground line A3 ofthe cable 40 is connected to a ground terminal (GND) of the circuitboard 25 through the filter circuit. The power supply line A2 of thecable 40 is connected to an internal power supply through the filtercircuit.

FIG. 14 is a diagram for explaining a method of connecting a shieldplate to a ground line in an in-vehicle camera according to the relatedart. In the method according to the related art, as illustrated in FIG.14, a ground line A3 and a drain line are connected to a terminal baseof a circuit board 25 individually, connected to the surface of thecircuit board 25, and then connected to the filter circuit. A shieldplate 26 is connected to a ground terminal (GND) of the circuit board25. In this case, if the connector of the cable 40 is connected to thecircuit board 25, the shield plate 26, the ground terminal of thecircuit board 25, and the ground line A3 and the drain line of the cable40 are electrically connected together. However, in this case,electrostatic discharge occurring in the shield plate 26 will certainlypass through the circuit board 25.

To eliminate the problem, in this embodiment, as illustrated in FIG. 15,the ground line A3, the drain line, and the shield plate 26 areelectrically connected to each other in the vicinity of the end of thecable 40. The ground line A3 is electrically connected to the groundterminal (GND) of the circuit board 25 through the filter circuit. Inthis case, if electrostatic discharge occurs in the shield plate 26, theimpedance of the conduction line passing along the shield plate 26 andthe drain line is lower than the impedance of the conduction linepassing along the shield plate 26, the ground line A3, the filtercircuit, and the ground terminal (GND) of the circuit board 25. For thisreason, the electrostatic discharge occurring in the shield plate 26does not pass through the circuit board 25.

In order to provide adequate shielding characteristics of the shieldplate 26 against electromagnetic waves emitted from the circuit board25, a filtering constant of the filter circuit may be adjusted.Moreover, the circuit board 25 is enclosed in the shield plate 26connected to the ground line, and it is possible to provide adequateshielding performance.

FIG. 16 is a diagram for explaining another method of connecting theshield plate to the ground line in the in-vehicle camera of thisembodiment. As illustrated in FIG. 16, the shield plate 26 may befurther connected to the ground terminal (GND) of the circuit board 25.In this case, it is possible to provide an increased shieldingcharacteristic of the shield plate 26 against electromagnetic wavesemitted from the circuit board 25.

As described in the foregoing, the ground line A3 and the shield plate26 are electrically connected to each other with low impedance at theend of the cable 40 on the side of the in-vehicle camera 20, and theground line A3 is connected to the ground terminal of the circuit board25 through the filter circuit. This connecting procedure can be easilyperformed when attaching the cable 40 to the in-vehicle camera 20.

Referring back to FIG. 2, in the back monitoring device of thisembodiment, the main controller 33 of the information processing device30 controls operation of the whole back monitoring device 10. The maincontroller 33 determines whether there is a danger, based on an outputsignal of the in-vehicle camera 20. For example, when a person, anothervehicle, a bicycle, or an obstacle exists at the rear of the vehicle 1and a collision or a rear-end collision is likely to occur, the maincontroller 33 determines that there is a danger, and outputs alarminformation to both the display unit 32 and the voice/alarm generatingunit 35.

The display unit 32 is disposed in the vicinity of the driver's seat ofthe vehicle 1 so that a driver can easily see a screen of the displayunit 32. A display image indicated by the analog video signal receivedfrom the in-vehicle camera 20 through the analog signal line A1 of thecable 40 is displayed on the screen of the display unit 32. If alarminformation is received from the main controller 33, the display unit 32displays a corresponding alarm message.

As illustrated in FIG. 17, the voice/alarm generating unit 35 includes avoice synthesizer 61, an alarm signal generator 62, and a loudspeaker63. The voice synthesizer 61 stores a plurality of voice data items. Ifalarm information is received from the main controller 33, the voicesynthesizer 61 selects a corresponding one of the voice data items withrespect to the received alarm information and outputs the selected dataitem to the loudspeaker 63.

If alarm information is received from the main controller 33, the alarmsignal generator 62 generates a corresponding alarm signal with respectto the received alarm information and outputs the generated alarm signalto the loudspeaker 63.

If it is determined that there is a danger, the main controller 33stores the output signal of the in-vehicle camera 20 into the memoryunit 34.

As is apparent from the foregoing, the sensing device according to thepresent disclosure is constituted by the back monitoring device 10 ofthis embodiment. The camera unit according to the present disclosure isconstituted by the in-vehicle camera 20 and the cable 40 in thisembodiment. A monitoring control device by the present disclosure isconstituted by the main controller 33 and the voice/alarm generatingunit 35 in this embodiment.

As described above, in the back monitoring device 10 of this embodiment,the shield plate 26 with which the circuit board 25 of the in-vehiclecamera 20 is enclosed is connected to the ground line A3 and the drainline in the vicinity of the end of the cable 40. According to the backmonitoring device 10 of this embodiment, an electrostatic dischargeoccurring in the shield plate 26 can be transferred to the ground lineof the power-supply unit 50 through the drain line, without passingthrough the circuit board 25. It is thus possible to eliminate theproblem of destruction of the electronic parts due to electrostaticdischarge. It is also possible to provide an increased resistance tostatic electricity for the in-vehicle camera 20.

Because the circuit board 25 of the in-vehicle camera 20 is enclosedwith the shield plate 26 which is set to the ground potential, it ispossible to provide adequate EMI measures against electromagnetic waves.Accordingly, it is possible to provide the in-vehicle camera 20 which iscapable of providing a high resistance to electrostatic discharge andgood performance of shielding electromagnetic waves with low cost.

Because the block 41 of the resin molding is attached to the portion ofthe cable 40 in the vicinity of the end of the cable 40 and the block 41is fixed to the camera housing 22 via the O-ring, it is possible toprovide good waterproofing performance of the in-vehicle camera 20. Theworkability at the time of attaching the cable 40 to the in-vehiclecamera 20 can be improved. It is also possible to provide good tensilestrength for the cable 40.

The shield plate 26 in the above-described embodiment may be replacedwith a conductive material which is painted or vapor-deposited to theinternal wall of the camera housing 22. In this case, it is necessarythat the conductive material of the front case 22A and the conductivematerial of the rear case 22B are electrically connected to each otherat the time of assembly.

In the above-described embodiment, the camera housing 22 is made of aresin molding. However, the present disclosure is not limited to thisembodiment. For example, the camera housing 22 may be made of analuminum die-cast component. In this case, the camera housing 22 servesas the shield plate 26 and the shield plate 26 may be omitted.

Instead of the cable 40 in the above-described embodiment, a cable 40Aas illustrated in FIG. 18 may be used. In the cable 40A, the analogsignal line A1 is a coaxial line in which the core conductor is enclosedwith an insulator B, a shield material F, and an insulator (sheath) E.In this case, control of the impedance between the analog signal line A1and the shield material F is possible, and degradation of the analogvideo signal can be prevented by adjusting the impedance to 50 ohms or75 ohms, etc. In this case, the shield material F of the coaxial linemay be used as a ground conductor element for taking preventive measuresagainst electromagnetic waves and electrostatic discharge.

Instead of the cable 40 in the above-described embodiment, a cable 40Bas illustrated in FIG. 19 may be used. The cable 40B includes two groundlines A3. In this case, the shield material F may be omitted. Althoughthis cable 40B is inexpensive, the cable tends to be influenced byexternally radiated noise and tends to emit electromagnetic waves fromthe cable itself. For this reason, the cable 40B may be arranged toinclude a twisted pair of one ground line A3 and the analog signal lineA1, and a twisted pair of the other ground line A3 and the power supplyline A2. In this case, one of the two ground lines A3 may be used as aground conductor element for taking preventive measures againstelectromagnetic waves and electrostatic discharge.

Instead of the cable 40 in the above-described embodiment, a cable 40Cas illustrated in FIG. 20 may be used. The cable 40C includes no groundline A3. In this case, the drain line in the cable 40C is connected tothe ground terminal of the circuit board 25 through the filter circuitas illustrated in FIG. 21. Namely, the drain line may be used as aground conductor element for taking preventive measures againstelectromagnetic waves and electrostatic discharge.

In the above-described embodiment, the cable 40 includes a single analogsignal line. However, the present disclosure is not limited to thisembodiment. For example, the cable 40 may further include two or morecontrol signal lines. These control signal lines may be used to transmitcontrol signals for displaying an enlarged image of a portion of adisplay image, or for performing initial adjustment of the position fordisplaying a vehicle width line image superimposed on a display image.

In the above-described embodiment, an analog video signal is output fromthe in-vehicle camera 20. However, the present disclosure is not limitedto this embodiment. For example, a digital video signal may be outputfrom the in-vehicle camera 20. However, in this case, it is necessarythat additional signal lines be included in the cable 40. Moreover, itis necessary to provide a signal processor circuit which is inconformity with the digital video signal output from the in-vehiclecamera 20.

In the above-described embodiment, the in-vehicle camera 20 is attachedto the rear of the vehicle 1 and used for the back monitoring device 10.However, the present disclosure is not limited to this embodiment. Forexample, the in-vehicle camera 20 may be attached to the front of thevehicle 1 and used for a monitoring device which monitors an imageindicating the surroundings of the vehicle 1 at the front thereof.Alternatively, the in-vehicle camera 20 may be attached to the side ofthe vehicle 1 and used for a monitoring device which monitors an imageindicating the surroundings of the vehicle 1 on the side thereof.

In the above-described embodiment, the CMOS image sensor is used as theimage sensor of the camera unit. However, the present disclosure is notlimited to this embodiment. For example, a CCD (charge-coupled device)image sensor may be used as the image sensor of the camera unit. In thiscase, a signal processor circuit which is in conformity with the CCDimage sensor may be used.

In the above-described embodiment, the lens system 21 is made up of sixlenses. However, the present disclosure is not limited to thisembodiment.

In the above-described embodiment, the circuit board is made up of asingle substrate. However, the present disclosure is not limited to thisembodiment. For example, the circuit board may be made up of two or moresubstrates.

Specifically, as illustrated in FIG. 22, the circuit board may bearranged to include a circuit board 25A and a circuit board 25B, and theshield plate 26 may be include holding parts or holding mechanisms forholding the circuit board 25B.

In the above-described embodiment, the ground line A3 and the drain lineare connected together at the end of the cable 40 in the −X direction,and the drain line and the shield plate 26 are connected together by alead wire. However, the present disclosure is not limited to thisembodiment. In this respect, some modifications of the above-describedembodiment will be described in the following.

<Modification 1>

In the modification 1, as illustrated in FIG. 23A, the three insulatedwires and the shield material F are exposed at the end of the cable 40in the −X direction, and the exposed shield material F is turned up sothat the insulating material E is enclosed with the turned-up shieldmaterial F. As illustrated in FIG. 23B, a branch line from the groundline A3 is provided and the branch line is turned up to the turned-upshield material F.

As illustrated in FIG. 25, a metal component 51 is crimped to the end ofthe cable 40 so that the branch line and the turned-up shield material Fare contained in and electrically connected to each other by the metalcomponent 51. As illustrated in FIGS. 24A to 24C, the metal component 51includes rectangular portions 52 at two locations on the circumferencethereof, each of which is formed into a slit with three cut portions.The metal component 51 is made of a resilient metallic material.

As illustrated in FIG. 26A, each of the rectangular portions 52 of themetal component 51 is bent outward. As illustrated in FIG. 26B, a block42 which is made of a resin molding and includes two through holes isbonded to a portion of the cable 40 in the vicinity of the end of thecable 40, with the bent part of each rectangular portion 52 beingexposed from the block 42.

In this case, as illustrated in FIG. 27, when attaching the cable 40 tothe in-vehicle camera 20, the rectangular portions 52 of the metalcomponent 51 are in contact with the shield plate 26 by simply insertingthe end of the cable 40 in the −X direction into the camera housing 22.Namely, the shield plate 26, the shield material F, and the ground lineA3 can be electrically connected to the ground terminal (GND) of thecircuit board 25 through the filter unit. In this case, the metalcomponent 51 may provide a resistance to removal of the cable 40.

<Modification 2>

In the modification 2, as illustrated in FIG. 28A, the ground line A3and the drain line are connected together at the end of the cable 40 inthe −X direction, and the drain line and an L-shaped metal plate 53 areconnected together by a lead wire.

As illustrated in FIG. 28B, a block 43 which is made of a resin moldingand includes two through holes is bonded to a portion of the cable 40 inthe vicinity of the end of the cable 40 with a part of the metal plate53 being exposed. In this example, the outside surface of the metalplate 53 in the −Z direction is exposed.

As illustrated in FIG. 29, the shield plate 26 in this case is formedwith a leaf spring 27, and when the cable 40 is attached to thein-vehicle camera 20, the metal plate 53 and the leaf spring 27 of theshield plate 26 are in contact with each other by simply inserting theend of the cable 40 in the −X direction into the camera housing 22.Namely, the shield plate 26, the shield material F, and the ground lineA3 can be electrically connected to the ground terminal (GND) of thecircuit board 25 through the filter unit. In this case, the metal plate53 has a simple configuration, and the cable processing and the handlingof the cable 40 can be performed easily. The metal plate 53 may beformed to have a flat surface which is in contact with the leaf spring27 of the shield plate 26.

<Modification 3>

In the modification 3, as illustrated in FIGS. 30A and 30B, a cap-likemetal component 54 including an opening which the three insulated wiresand the drain line pass through at the end of the cable 40 in the −Xdirection is used.

In the modification 3, the ground line A3 and the drain line areconnected together at the end of the cable 40 in the −X direction, andthe drain line and the metal component 54 are connected together by alead wire.

As illustrated in FIG. 31, a block 44 which is made of a resin moldingand includes two through holes is bonded to a portion of the cable 40 inthe vicinity of the end of the cable 40 with the surface of the metalcomponent 54 being exposed.

In this case, as illustrated in FIG. 32, the shield plate 26 is formedwith leaf springs 27, and when the cable 40 is attached to thein-vehicle camera 20, the metal component 54 and the leaf springs 27 ofthe shield plate 26 are in contact with each other by simply insertingthe end of the cable 40 in the −X direction into the camera housing 22.Namely, the shield plate 26, the shield material F, and the ground lineA3 can be electrically connected to the ground terminal (GND) of thecircuit board 25 through the filter unit. In this case, there is noclearance except for the opening of the metal component 54 which thethree insulated wires and the drain line pass through, and it ispossible to provide increased shielding performance of electromagneticwaves.

The shield plate 26 may be formed with three or more leaf springs 27 inorder to improve the shielding performance of electromagnetic waves. Inthis case, the metal component 54 may be arranged to include therectangular portions which are the same as those in the above-describedmodification 1. At this time, the leaf springs 27 of the shield plate 26may be omitted.

<Modification 4>

In the modification 4, the end of the cable 40 in the −X direction isessentially the same as that in the above-described modification 1, andthe camera housing 22 is made of a metallic material. As illustrated inFIG. 33, when attaching the cable 40 to the in-vehicle camera 20, therectangular portions 52 of the metal component 51 and the rear case 22Bare in contact with each other by simply inserting the end of the cable40 in the −X direction into the camera housing 22. Namely, the rear case22B, the shield material F, and the ground line A3 can be electricallyconnected to the ground terminal (GND) of the circuit board through thefilter unit.

When painting is performed on the outer surface of the camera housing,it is preferred that the painting process is not performed for theportions of the camera housing which are to be contacted by therectangular portions 52, and a plating process is performed for suchportions.

<Modification 5>

In the modification 5, as illustrated in FIG. 34, a spring component 55to which the ground line A3 and the drain line are connected by leadwires at the end of the cable 40 in the −X direction is used. A block 45which is made of a resin molding and includes two through holes isbonded to a portion of the cable 40 in the vicinity of the end of thecable 40 with a part of the spring component 55 being exposed from theblock 45.

In this case, the camera housing 22 is made of a metallic material, and,as illustrated in FIG. 35, when attaching the cable 40 to the in-vehiclecamera 20, the spring component 55 and the rear case 22B are in contactwith each other by simply inserting the end of the cable 40 in the −Xdirection into the camera housing 22. Namely, the rear case 22B, theshield material F, and the ground line A3 can be electrically connectedto the ground terminal (GND) of the circuit board through the filterunit.

In the above-described embodiment, the insulated wires are exposed fromthe end of the cable 40. Alternatively, the insulated wires at the endof the cable 40 and an FPC (flexible printed circuit) may be connectedtogether within a block made of a resin molding and the wiring in theFPC may be arranged in the block. In this case, the space for the wiringcan be reduced.

In the above-described embodiment, the plural lenses are held in thefront case. Alternatively, the plural lenses may be held in alens-barrel, and the lens-barrel may be attached to the front case.

As described in the foregoing, according to the present disclosure, itis possible to provide a camera unit which can provide high resistanceto electrostatic discharge and good shielding performance ofelectromagnetic waves with low cost. According to the presentdisclosure, it is possible to provide a sensing device which can provideincreased reliability with low cost.

The present disclosure is not limited to the above-describedembodiments, and variations and modifications may be made withoutdeparting from the scope of the present invention.

What is claimed is:
 1. A camera unit comprising: an image sensor; acircuit board in which a signal processor circuit to process an outputsignal of the image sensor is formed; a cable including at least asignal conductor element and a ground conductor element and connected atone end to the circuit board; a metal housing component to accommodatethe image sensor and the circuit board therein; and a metal componentdisposed at the end of the cable and connected to the ground conductorelement, wherein the ground conductor element is connected to both aground terminal of the circuit board and the metal housing component ina vicinity of the end of the cable where the cable is connected to thecircuit board, and wherein the ground conductor element is connected tothe metal housing component through the metal component in the vicinityof the end of the cable.
 2. The camera unit according to claim 1,wherein the metal component is fixed to a portion of the cable in thevicinity of the end of the cable in a state in which the metal componentis connected to the ground conductor element, and the metal componentincluding a contact portion which is in contact with the metal housingcomponent when the cable is connected to the circuit board.
 3. Thecamera unit according to claim 1, wherein the metal component is fixedto a portion of the cable in the vicinity of the end of the cable in astate in which the metal component is connected to the ground conductorelement, and the metal housing component including a contact portionwhich is contacted by the metal component when the cable is connected tothe circuit board.
 4. The camera unit according to claim 1, wherein themetal component has a cap-like configuration and is formed to enclosethe end of the cable therewith, and an opening being formed in a bottomsurface of the metal component, and the signal conductor element and theground conductor element passing through the opening of the metalcomponent.
 5. The camera unit according to claim 1, wherein the cablefurther includes a ground line and the ground line is connected to theground conductor element in the vicinity of the end of the cable.
 6. Thecamera unit according to claim 1, wherein the image sensor is an imagesensor with a built-in lens system.
 7. The camera unit according toclaim 1, wherein the image sensor is a CMOS image sensor.
 8. The cameraunit according to claim 1, wherein the image sensor is a CCD imagesensor.
 9. A sensing device comprising: a camera unit to capture animage indicating surroundings of the camera unit; and a display unit todisplay image information based on an output signal of the camera unit,the camera unit comprising: an image sensor; a circuit board in which asignal processor circuit to process an output signal of the image sensoris formed; a cable including at least a signal conductor element and aground conductor element and connected at one end to the circuit board;a metal housing component to accommodate the image sensor and thecircuit board therein; and a metal component disposed at the end of thecable and connected to the ground conductor element, wherein the groundconductor element is connected to both a ground terminal of the circuitboard and the metal housing component in a vicinity of the end of thecable where the cable is connected to the circuit board, and wherein theground conductor element is connected to the metal housing componentthrough the metal component in the vicinity of the end of the cable. 10.The sensing device according to claim 9, further comprising a memoryunit to store the output signal of the camera unit.
 11. The sensingdevice according to claim 9, wherein the sensing device is installed ina vehicle and comprises a monitoring control device to determine whetherthere is a danger based on the output signal of the camera unit, themonitoring control device outputting alarm information to the displayunit when it is determined that there is a danger.